The present disclosure relates to a non-axisymmetric fixed or variable fan nozzle for a fan section of a gas turbine engine.
Conventional fan nozzles, corresponding to clean inflow fans, are axi-symmetric—that is they are symmetric around the fan rotation axis. For boundary layer ingestion propulsion systems, ingested boundary layer flow from an airframe creates a velocity and total pressure distortion locally in the region of the fan adjacent to the airframe. This distortion has little distance in which to mix or otherwise re-distribute within the inlet between the highlight and the fan face. Further, this distortion presents challenges to fan performance, aeromechanics, and operability. It is desirable to overcome these issues and reduce the adverse impacts of boundary layer ingestion on the fan component of a gas turbine system.